Packing containers of the type mentioned above are primarily used for individually packing larger projectiles, such as grenades and the like.
Numerous containers are known for this purpose, such containers consisting of card board, glass fiber reinforced plastics, blow moldable plastics or even wood. Containers of cardboard and wooden boxes are not used anymore in view of the better characteristics of the plastic containers.
Packing containers made of glass fiber reinforced plastics have the advantage that the inherent hardness by which these materials are characterized permits wide savings in that the walls of the packing containers can be made thin. Yet improvements in the shaping of the packing containers in order to adapt such containers to the respective goods to be packed can only be achieved within certain limits because of the process of manufacture of such containers which process is determined by the material used. Therefore, the packing containers of glass fiber reinforced material have a simple round or angular shape of the kind of a tube, and has to be fitted with special damping inserts for protecting their respective contents. Thus normally felt or soft rubber strips were placed in the containers in order to center the contents within the tube and, on the other hand, afford some protection against impact. However, as the containers could not be made to any large size but instead corresponded approximately to the size of the grenade to be received these damping strips were relatively thin so that genuine damping was not obtained. Furthermore, these damping or spacing strips could become displaced during transport and thus lose their rather little effect altogether.
The mechanical strength values of the packing container of glass fiber reinforced plastics were to guarantee that the contents would be protected. For this reason the containers were relatively stiff. This in turn caused the disadvantage that the containers, then being stressed by falling or by impact, either could become destroyed or permanently deformed. As there was only little or no damping, the contents could suffer damage as well. Renewed use of the packing container was out of the question.
A container made out of fibrous material is known from the U.S. Pat. No. 2,356,969 to J. J. Blum. The fibrous material of this container consists of a mixture of fibrous pulp and a thermoplastic binder. Although this packing container is designed for the packing, storage and shipment of ammunition, this known container is not safe enough when subjected to shock forces. An impact on the part of this container surrounding the case portion of the shell is transmitted to this case portion substantially undamped. An impact on the outer tubular envelope of this container in the area of the nose portion of the projectile is not sufficiently damped before such impact is transmitted to the projectile. This is because the outer envelope will break when subjected to a point impact because of the material used.
An improvement with respect to the containers mentioned above is a container known from the German published application 1,940,211. This container is made out of a blow moldable thermoplastic material and has damping ribs to support the portion of packed projectile. However, this container consists only of one container envelope so that impact on the packing in various areas of such packing is transmitted directly to the projectile. Considering the fact that not only the nose portion of the projectile is susceptible to shock but also the case portion containing the explosive material, it is highly undesirable to leave any of these portions of the projectile unprotected against impact and shock forces.
In view of the above, the main object of this invention is to design a plastic packing container which provides improved best possible protection of the contents against impact and shock forces acting from outside. It is also an object of the present invention to provide a packing container which permits easier handling and has longer lifetime. It is a further object of the present invention to provide a packing container of plastics material which is shaped to conform with the packed goods so that the packed goods are supported safely.
It is a further object of the present invention to provide a packing container of plastics material adapted to be stacked as desired, where the packed goods may be moved from the container in the stacked condition without disturbing the stack of the containers.